1. Field of the Invention
The invention relates to a lamp. Particularly, the invention relates to a light-emitting diode (LED) lamp.
2. Description of Related Art
A light-emitting diode (LED) is a semiconductor device, and a material of a light emitting chip thereof is mainly a compound of III-V group chemical elements, for example, gallium phosphide (GaP) or gallium arsenide (GaAs), and a light-emitting principle of the LED is to convert electric energy into light energy. In detail, by applying a current to the compound semiconductor, excessive energy is released in form of light through combination of electrons and holes. Since the light-emitting principle of the LED is not to emit light through heating or discharging, a service life of the LED may be more than one hundred thousand hours. Moreover, the LED further has advantages of fast response speed, small size, low power consumption, low pollution, high reliability and suitable for mass production, etc., so that the LED has a very wide application range, which may be used as a light source for large-scale billboards, traffic lights, mobile phones, scanners, fax machines and LED lamps, etc.
Taking the LED lamp as an example, the LED lamp may have a divergent light source or a convergent light source according to a light shape thereof. The divergent light source is generally used for environmental lighting, and the convergent light source is used for lighting a specific object. Presently, most of the LED lamps have a single light shape, and when the environmental lighting and lighting of the specific object are simultaneously required, besides the LED lamp having the divergent light source is installed, the LED lamp having the convergent light source is also required, which may occupy relatively more space, and a circuit layout thereof is relatively complicated.
Taiwan patent publication No. 200946834 discloses a lighting device, in which a transparent reflection cover is a high optical material containing light divergent micro-particles, which strengthens a refraction and diffusion effect of the light and increases a horizontal light emitting effect. Taiwan patent No. M303327 discloses a lamp base, and an LED light source is disposed at a side of a light emitting plate, so as to provide even planar light source through the light emitting plate. Taiwan patent publication No. 200835887 discloses a lighting apparatus, in which a light guiding layer has a plurality of pores, and the LED light sources are respectively disposed in the pores, and the light emitted from the LED light source enters the light guiding layer and emits to external through a bottom surface of the light guiding layer. U.S. Pat. No. 6,315,432 discloses an LED device, in which a spherical container is spherically connected to a positioning base, and the LED light source is contained in the spherical container, and a lighting direction thereof is adjusted along with rotation of the spherical container.